I've seen \ls used to get the unaliased system version of ls. Likely useful for those commands where you don't want the aliased version and aren't sure if they live in /bin or /usr/bin.
Nice, didn't know about "\ls"! I wonder what's the difference between "\ls" and "command ls". Yes, it's a bit longer to type but the output is the same, I'm asking about what happens behind the scenes.